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Research Article

Distribution of Respiratory Droplets in Enclosed Environments under Different Air Distribution Methods

Naiping Gao1( ), Jianlei Niu2, Lidia Morawska3
Department of Refrigeration and Thermal Engineering, College of Mechanical Engineering, Tongji University, Siping Road 1239#, Shanghai, China
Department of Building Services Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong, China
International Laboratory for Air Quality and Health, School of Physical and Chemical Sciences, Queensland University of Technology, 2 George Street, Brisbane Q 4001, Australia
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Abstract

The dispersion characteristics of respiratory droplets are important in controlling transmission of airborne diseases indoors. This study investigates the spatial concentration distribution and temporal evolution of exhaled and sneezed/coughed droplets within the range of 1.0-10.0μm in an office room with three air distribution methods, specifically mixing ventilation (MV), displacement ventilation (DV), and under-floor air distribution (UFAD). The diffusion, gravitational settling and deposition mechanism of particulate matter were accounted by using an Eulerian modeling approach with one-way coupling. The simulation results indicate that exhaled droplets up to 10μm in diameter from normal human respiration are uniformly distributed in MV. However, they become trapped in the breathing zone by thermal stratifications in DV and UFAD, resulting in a higher droplet concentration and an increased exposure risk to other room occupants. Sneezed/coughed droplets are more slowly diluted in DV/UFAD than in MV. Low air speed in the breathing zone in DV/UFAD can lead to prolonged human exposure to droplets in the breathing zone.

Keywords

respiratory dropletsair distributiontransmissionairborne disease

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Building Simulation
Volume 1 Issue 4,
December 2008
Pages 326-335
DOI: 10.1007/s12273-008-8328-0
Cite this article:
Gao N, Niu J, Morawska L. Distribution of Respiratory Droplets in Enclosed Environments under Different Air Distribution Methods. Building Simulation, 2008, 1(4): 326-335. https://doi.org/10.1007/s12273-008-8328-0
Part of a topical collection:
Ventilation, Simulation and Infectious Disease Control in Built Environment

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Received: 15 October 2008
Revised: 31 October 2008
Accepted: 04 November 2008
Published: 05 December 2008
© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2008

© Tsinghua Press and Springer-Verlag 2008
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